3D game development with microsoft silverlight 3

Table of ContentsTime for action – preparing the development environment 8 Time for action – creating the raster digital content 14 Time for action – installing tools to manipulate scala

3D Game Development with

Microsoft Silverlight 3

Beginner's Guide

A practical guide to creating real-time responsive online 3D games in Silverlight 3 using C#, XBAP WPF, XAML, Balder, and Farseer Physics Engine

Gastón C Hillar

BIRMINGHAM - MUMBAI

3D Game Development with Microsoft Silverlight 3

Beginner's Guide

Copyright © 2009 Packt Publishing

All rights reserved No part of this book may be reproduced, stored in a retrieval system,

or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.Every effort has been made in the preparation of this book to ensure the accuracy of the information presented However, the information contained in this book is sold without warranty, either express or implied Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book

Packt Publishing has endeavored to provide trademark information about all of the

companies and products mentioned in this book by the appropriate use of capitals

However, Packt Publishing cannot guarantee the accuracy of this information

First published: September 2009

Cover Image by Gastón Hillar and Adline Swetha Jesuthas

Cover image for illustrative purposes only

Cover Work

Aparna Bhagat

About the Author

Gastón C Hillar has been working with computers since he was eight He began

programming with the legendary Texas TI-99/4A and Commodore 64 home computers

in the early 80's

He has a Bachelor's degree in Computer Science in which he graduated with honors, and

he also has an MBA (Master in Business Administration) in which graduated with an

outstanding thesis He has worked as a developer, an architect, and project manager for many companies in Buenos Aires, Argentina Now, he is an independent IT consultant and a freelance author always looking for new adventures around the world He also works with electronics (he is an electronics technician) He is always researching new technologies and writing about them He owns an IT and electronics laboratory with many servers, monitors, and measuring instruments

He has written another book for Packt, "C# 2008 and 2005 Threaded Programming:

Beginner's Guide".

He contributes to Dr Dobb’s Go Parallel programming portal parallel/ and he is a guest blogger at Intel Software Network http://software.intel.com

http://www.ddj.com/go-He is the author of more than 40 books in Spanish about computer science, modern

hardware, programming, systems development, software architecture, business applications, balanced scorecard applications, IT project management, the Internet, and electronics

He usually writes articles for the Spanish magazines "Mundo Linux", "Solo Programadores" and "Resistor"

He lives with his wife, Vanesa, and his son, Kevin When not tinkering with computers, he enjoys developing and playing with wireless virtual reality devices and electronics toys with his father, his son, and his nephew Nico

You can reach him at: gastonhillar@hotmail.com

You can follow him on Twitter at: http://twitter.com/gastonhillar

Gastón's blog is at: http://csharpmulticore.blogspot.com

While writing this book, I was fortunate enough to work with an excellent team at Packt Publishing Ltd, whose contributions vastly improved the presentation of this book James Lumsden helped me to transform the idea in the final book and to take my first steps

working with a new Beginner's Guide Zainab Bagasrawala made everything easier with both her incredible time management and patience Darshana Shinde helped me realize my vision for this book and provided many sensible suggestions regarding the text, the format and the flow The reader will notice her great work Arani Roy made the sentences, the paragraphs, and the code easier to read and to understand He has added great value to the final drafts.Special thanks go to Einar Ingebrigtsen (http://www.ingebrigtsen.info), Balder's lead developer Einar's work inspired this book He made it possible to have a game engine for Silverlight 3 This book was possible because Einar helped me with each new feature added to Balder His outstanding knowledge on game development made it possible to work with an excellent engine I also have to thank Petri Wilhelmsen, another Balder's developer who also helped to improve the engine I would like to thank my technical reviewers and proofreaders, for their thorough reviews and insightful comments I was able to incorporate some of the knowledge and wisdom they have gained in their many years in the software development industry The examples, the pictures and the code include the great feedback provided by Tarkan Karadayi Tarkan helped me a lot to include better and shorter code to simplify the learning process I would like to thank Mark Dawson, Kit3D's developer Mark's work also inspired the development of many simple 3D applications using previous Silverlight versions and his simple yet powerful engine I wish to acknowledge Bill Reiss, as he worked

to show the world that Silverlight games were possible He was another great source of inspiration for my work on this book I would like to thank Doug Holland, as his blog posts at Intel Software Network always helped me to stay tuned with tips related to many products used in this book

I must acknowledge David Barnes, Beginner's Guide Series Editor at Packt His help in my previous book and his wisdom is also part of this new one I must also thank Shilpa Dube, Rakesh Shejwal and Rajashree Hamine They helped me in my previous book written for Packt and this new one was much easier bearing in mind their excellent tips

Special thanks go to my wife, Vanesa S Olsen, my son Kevin, my nephew, Nicolas, my father, Jose Carlos, who acted as a great sounding board and participated in many hours of technical discussions, my sister, Silvina, who helped me when my grammar was confusing and my mother Susana They were always supporting me during the production of this book.

About the Reviewer

Tarkan Karadayi has been writing code since age 14 He has a Masters in Computer Science and is currently working as a Lead Developer

I would like to thank my wife Anna, my parents and my three sons Taran,

Kyle, and Ryan for their love and support

Table of Contents

Time for action – preparing the development environment 8

Time for action – creating the raster digital content 14

Time for action – installing tools to manipulate scalable digital content 19

Time for action – creating the scalable digital content in XAML 22

Time for action – testing the scalable digital content using XamlPad 26Editing vector illustrations using Expression Design 27

Time for action – creating Silverlight applications 29Time for action – building and running Silverlight applications 33

Time for action – building and running the XBAP WPF applications 38

Time for action – transforming media using the GPU 45

[ ii ]

Time for action – shaking many illustrations at the same time 49

Time for action – detecting GPU-acceleration problems 54

Creating encapsulated object-oriented characters 56

Time for action – creating User Control classes to hold images 56

Time for action – creating sprites based on XAML vector-based graphics 72

Time for action – creating a specialized sprite management class 76Taking full advantage of object-oriented capabilities 80

Time for action – creating a superclass for some characters 82Time for action – creating the subclasses for the characters 84Time for action – creating methods for the game loop 89

Time for action – detecting collisions between 2D characters 99

[ iii ]

Time for action – displaying a 3D model in a 2D screen with WPF 117

Interacting with 3D elements using Expression Blend 131

Displaying a 3D model in a 2D screen with Silverlight 138

Controlling the position, the direction, and the up vector 146

Time for action – understanding perspective and orthographic cameras 157

Time for action – controlling cameras on the fly 160

Chapter 6: Controlling Input Devices to Provide Great Feedback 165

Time for action – creating a keyboard manager class 166

Time for action – programming the input control in the game loop 169Time for action – mapping a gamepad to the keyboard 173

[ iv ]

Time for action – creating a mouse manager class 179

Time for action – using the mouse manager in the game loop 181

Time for action – rotating cameras using input devices 185

Considering deployment's additional requirements 190Time for action – understanding sticks and buttons 190Understanding the steering wheel as an input device 192Time for action – testing the input devices with a DirectInput wrapper 193Understanding the analog axis for a steering wheel 195

Time for action – adapting a joystick manager class 197Time for action – using the steering wheel in the game loop 200

Time for action – exporting 3D models from DCC tools to Silverlight 212Displaying a 3D model using textures in a 2D screen with Silverlight 213

Displaying lights, shadows, materials, and textures 222

Time for action – working with lights and understanding shadows 222

Time for action – creating a new game superclass to generalize

[ v ]

Time for action – specializing a game superclass 233Time for action – creating a subclass for a 3D character 234

Using the World matrix in order to perform transformations to meshes 241

Time for action – animating models with skeletons and bones 247

Time for action – adding an Actor with skeletons and bones

Chapter 9: Adding Realistic Motions Using a Physics Engine 255Using physical principles in games to beat invaders 256

Time for action – installing Farseer Physics Engine 256Time for action – adding parallel physics bodies and

Working with Farseer Physics Engine in XBAP WPF applications 270

Detecting collisions between 3D characters 275

Time for action – detecting collisions between 3D characters 279

[ vi ]

Using engines to improve collision detection precision 285

Using artificial intelligence in games to control 3D characters 288

Time for action – simulating fluids with movement 315

Time for action – creating a subclass for a complex asteroid belt 318Using an Actor to represent a wave in the background 321Time for action – adding an asteroid belt background to the game 322

Time for action – creating a score gauge showing text 332

Time for action – creating a bonus gauge showing text 341

Time for action – creating a remaining lives gauge 345

Time for action – installing Windows Presentation Foundation 356

Time for action – adding screens to organize the game 361

Rendering a WriteableBitmap and using it as an ImageBrush 366

Time for action – changing the transition effect 368

Time for action – changing and improving the environments

Retrieving values for parameters using LINQ to XML 378

Using free applications to convert video formats 393

Taking advantage of GPU acceleration to scale videos 397

Working with a StoryBoard in XAML to animate a projection 401

Time for action – preparing audio files to use them in Silverlight 405

[ viii ]

Using free applications to convert audio formats 408Time for action – creating a class to handle audio concurrency 409Using a round robin algorithm to work with concurrent sounds 411Time for action – generating sounds associated to game events 412

It will help you learn to develop 3D games and interactive 3D scenes for a web site with animated models, with numerous examples and clear explanations packed with screenshots

to aid your understanding of every process After all of the code is written and the additional art assets edited, they are all compressed into zip files for easy availability and use

What this book covers

Chapter 1: Lights, Camera, and Action!: In this chapter, we will cover many topics that will

help us to understand the new tools and techniques involved in preparing 2D graphics to be used in Silverlight games This chapter is all about tools and graphics

Chapter 2: Working with 2D Characters: In this chapter, we will begin creating 2D characters

that move on the screen and we will learn to control their behavior in the 2D space We will

learn about GPU hardware acceleration, 2D vectors, resolutions, sprites, and animation Chapter 3: Combining Sprites with Backgrounds: In this chapter, we will control multiple sprites

created on demand We will animate several independent sprites at the same time, while responding to the keys pressed by the player to control characters and some game logic

Chapter 4: Working with 3D Characters: In this chapter, we will take 3D elements from

popular and professional 3D DCC tools and we will show them rendered in real-time on the screen We will learn a lot about 3D models, meshes, and 3D engines

Chapter 5: Controlling the Cameras: Giving Life to Lights and Actions: In this chapter, we

will learn everything we need to know about 3D cameras to be able to render our models

in real-time on a 2D screen from different angles We will change the values for their most important properties and we will be able to watch their effects in a rendered 3D view

[ 2 ]

Chapter 6: Controlling Input Devices to Provide Great Feedback: In this chapter, we will learn

everything we need to know about the most widely used gaming input devices We will be able to read values from them in order to control many aspects of our games

Chapter 7: Using Effects and Textures to Amaze: In this chapter, we will learn everything we

need to know about the process of enveloping a 3D model using textures We will be able

to take 3D elements from popular and professional 3D DCC tools and we will show them rendered in real-time on the screen with different textures and enlightened by many lights

Chapter 8: Animating 3D Characters: In this chapter, we will learn how to move, rotate, and

scale the 3D models in the 3D scenes We will use object-oriented capabilities to define independent behaviors for simple and complex 3D characters

Chapter 9: Adding Realistic Motions Using a Physics Engine: In this chapter, we will

simulate some laws of 2D and 3D physics We will learn to define gravity force, mass, drag coefficients, and moment of inertia to represent the physical properties of the bodies that define a model

Chapter 10: Applying Artificial Intelligence: In this chapter, we will detect collisions between

3D characters and we will define specific behaviors using artificial intelligence, persecution, and evasion algorithms

Chapter 11: Applying Special Effects: In this chapter, we will use advanced physics and special

effects We will generate gravity effects, we will add fluids with movements, and we will use transitions to determine different states in a game

Chapter 12: Controlling Statistics and Scoring: In this chapter, we will create gadgets to

display different kinds of information to the player on the screen We will also calculate different kinds of information in order to update the gauges Also, we will measure and improve the game’s overall performance

Chapter 13: Adding Environments and Scenarios: In this chapter, we will create menus and

attractive transitions We will add configuration options and we will save them using an isolated storage

Chapter 14: Adding Sound, Music, and Video: In this chapter, we will generate sounds

associated to game events We will also add presentation videos and background music

Appendix: Pop Quiz Answers: This appendix will include answers to all the pop quiz

questions chapter-wise

[ 3 ]

What you need for this book

You will need Visual C# 2008 (.NET Framework 3.5) with Service Pack 1, or greater—Visual C# 2010—installed

You can use the free Visual Web Developer 2008 Express Edition or greater

(http://www.microsoft.com/express/vwd/) However, you have to read

the documentation to consider its limitations carefully

Who this book is for

This book is designed primarily for C# developers with a basic knowledge of Visual Studio IDE who want to develop online 3D games using Silverlight, or create interactive 3D scenes for a web site with animated models No prior experience in 3D programming, 3D animation, and Silverlight is required

The book is also aimed at 3D developers who want to improve their online content by offering innovative 3D models in action

A block of code is set as follows:

private void Ghost_MouseMove(object sender, MouseEventArgs e)

{

// Get the mouse current position

Point point = e.GetPosition(cnvMovementTest);

// Set the canvas Left property to the mouse X position

[ 4 ]

New terms and important words are shown in bold Words that you see on the screen, in

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moves you to the next screen"

Warnings or important notes appear in a box like this

Tips and tricks appear like this

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[ 5 ]

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Lights, Camera, and Action!

We want to develop 3D games using Silverlight 3 We will need to work

hard in order to achieve this exciting goal First, we must understand some

fundamentals related to various tools and 2D graphics, and their relevance

to Silverlight 3 In this chapter, we will cover many topics that will help us

understand the new tools and techniques involved in preparing 2D graphics

to be used in Silverlight games This chapter is all about graphics.

In this chapter, we will:

Prepare a development environment to develop games using Silverlight 3

Recognize the digital art assets from an existing game

Create and prepare the digital content for a new 2D game

Understand the tools involved in a 2D game development process

Learn to manipulate, preview, and scale the digital content

Build and run our first graphics application using the digital content

UFOs in the sky!: Invaders

You love 3D games You have always wanted to develop a 3D game with amazing characters, dazzling scenarios, outstanding effects, and many skill levels And now you have the

opportunity A legendary game developer drives a new game contest He challenges

Silverlight developers to show him some ideas for a modern 2D Invaders game If he likes

a developer's idea, he will contract him to develop 3D games for his well-known gaming web site using Silverlight 3 This web site pays high wages to developers It is an incredible opportunity and you cannot miss this train Tickets, please!

[  ]

Developing 3D games is an exciting process, but it is also difficult However, working with

a 2D game before moving into the 3D world is a nice starting point That is exactly what we are going to do

During our journey, we will need to exploit our creativity as much as possible Game

development requires many heterogeneous skills However, the most important

ingredient is creativity.

We already know how to develop some applications using the C# programming language

However, RIAs (Rich Internet Applications) offer an exciting way ahead for game

development because they provide a rich experience for users without the need to install software on their computers Users expect RIAs to be like conventional downloadable games that offer amazing graphics, impressive performance, and a very interactive experience Silverlight is a great (and growing) RIA platform, and games are the next level to exploit in Silverlight 3D games represent our challenge in this book and we shall take full advantage

of our C# knowledge here

So, let's take our C#, XAML, and Silverlight development skills to the next level We want to take full advantage of modern technologies First of all, we must install the latest tools and begin working on some 2D games' basics Later, we will use that knowledge in developing 3D games using Silverlight 3, the newest kid on the block from Microsoft

The only requirements needed to develop 3D games using Silverlight are to understand the basics of the C# programming language, XAML code, and the Visual Studio IDE We will cover the rest of the requirements in our journey through the 3D game development world!Time for action – preparing the development environment

First, we must download and install various Silverlight development tools

We need to install Visual C# 2008 (.NET Framework 3.5) with Service Pack 1 or greater (Visual C# 2010) in order to successfully complete the installations provided here Installing Silverlight 3 Tools will uninstall the previous Silverlight versions We will not be able to create Silverlight 2 applications using Visual C# 2008 with Silverlight 3 Tools installed in our system Visual C# 2010 does not have this restriction because it allows us to choose the desired Silverlight version target

You can use the free Visual Web Developer 2008 Express Edition or greater (http://www.microsoft.com/express/vwd/) However, you have to read the documentation and consider its limitations carefully

[  ]

The following are steps for preparing the development environment:

1 Download the following files:

en.exe It is a commercial tool,

but the trial offers a free fully functional version for 30 days This tool will enable

us to transform vector assets to the appropriate format for use in Silverlight 3 Inkscape http://inkscape.org/

download/?lang=en

0.46.win32.

Inkscape-exe

It is a very complete free, open source, vector drawing program This tool will enable us to import many vector assets in different, popular file formats and export them to a format recognized by Expression Design Silverlight

aspx?familyid=9442b0f2-Silverlight3_

Tools.exe We must install it

to create Silverlight

3 applications in Visual Studio IDE using XAML and C# This will uninstall previous Silverlight

SDKs (Software Development Kits).

aspx?familyid=0A9773A7-Silverlight_

3_Docs.zip We must download

and decompress this file, as we will be needing access to the Silverlight 3 official documentation.

to use Expression Blend 3 to create rapid prototypes for some game scenes.

.NET RIA

Services http://www.microsoft.com/downloads/details.

3846-4564-b0c3-27972bca abce&displaylang=en

aspx?FamilyID=76bb3a07-RiaServices.

allows the creation of business applications that are capable of talking to our games

In the same link, there

is a PDF file available for download with interesting documentation about this framework Silverlight

It is convenient to download the latest stable release This toolkit provides a nice collection of Silverlight controls, components, and utilities made available outside the normal Silverlight release cycle It will

be really helpful to use these controls to provide many game statistics Besides,

it includes more Silverlight themes.

2. Run the installers in the same order in which they appear in the previous

list, and follow the steps to complete the installation wizards Take into

account that to install Silverlight 3 Tools for Visual Studio, you will need an

Internet connection for a small download when the wizard begins One of

the items enumerated under the Products affected by the software update: list is Download Preparation, as shown in the following screenshot:

[ 11 ]

3 Once the installations have successfully finished, run Visual Studio 2008 or Visual

Web Developer 2008 (or later) You will see the Microsoft Silverlight Projects

label displayed on the splash screen, as shown in the following picture:

details shows number 3 after the second dot (.) For example, 9.0.30730.126

indicates that Silverlight 3 is installed, as shown in the following picture:

What just happened?

We installed Silverlight 3 Tools for Visual Studio, Expression Blend 3 for Silverlight 3, NET RIA Services, and Silverlight Toolkit

Now, we have everything we need to begin creating and testing amazing 2D games using Silverlight 3 and C#

Time for action – recognizing digital art assets

One of the best ways of explaining a new game idea is showing it in a very nice picture This

is exactly what you want to do However, it is very difficult to find a new game idea from scratch Therefore, in working out how to impress the legendary game developer, you ask for some help in an 8-bit retro gaming community You meet a legendary space shooter games' expert and he shows you many remakes of the classic 8-bit Invader game—also known as

[ 13 ]

Space Invaders The remakes are too simple and they do not exploit modern widescreen displays, as they run in very low resolutions inside the web browsers A dazzling remake

of an Invaders game sounds like a very nice idea!

We are going to take a snapshot of the first scene of one of the most exciting 8-bit

implementations of the Invaders game—the legendary TI Invaders—as shown in the

following picture:

What just happened?

Looking at the TI Invaders scene picture, we can recognize the following digital art assets:

[ 14 ]

These assets are organized as shown in the following picture:

The aliens are organized in five rows and eleven columns There are four tents and just one ship to challenge all these aggressive invaders

Time for action – creating the raster digital content

This prehistoric game used a 256X192 pixels screen (49,152 pixels) We are going to prepare raster digital assets for the game optimized for a 1680X1050 pixels screen (1,764,000 pixels) The game should look nice when compared to the older version

The old version used 8X8 pixels raster digital assets In this new version, we can use 50X50 pixels raster digital assets

The creation of raster digital assets for a 2D game is very complex and requires professional skills Digital artists and graphic designers are very important members of a professional game development team They provide great quality digital assets to the programming team

company, http://turbomilk.com) They are ideal to use in the game.

PNG is an open, extensible image format with lossless compression

Silverlight 3 works great with PNG images I recommend not using the JPEG (Joint Photographic Experts Group) format for foreground digital assets or iconic graphics because it uses a lossy compression method that removes

some information from the image

First, we are going to download, manipulate, resize, and finally save the new versions of the new raster digital content for the game:

1 Download the PNG images for the green, blue, and red aliens, the tents, and the ship You can take some nice images from http://turbomilk.com/downloads/

2 Save all the original PNG images in a new folder (C:\Silverlight3D\

Invaders\GAME_PNGS), as shown in the following picture:

3 Open the images for the aliens, ship, and tents using an image-manipulation

tool You can use a free and open source software such as GIMP (the GNU Image

Manipulation Program) that is available at http://www.gimp.org, or a

commercial software such as Adobe Photoshop available at http://www.adobe.com, or free software such as Picasa available at http://picasa.google.com

[ 16 ]

4 Remove the shadows from the images because we are not going to use them as icons You can select the shadows and delete them using the magic wand tool (fuzzy select tool) It requires high precision in the selection to avoid deleting the original drawing Shadows have to be removed because we want to use them as raster content for the game, as shown in the following picture:

5 Remove the transparent pixels from the images (that is, erase the selection)

6 Resize the images for the aliens and the ship to 50X50 pixels square, while keeping proportions Save them in a PNG format using the following names:

ALIEN_01_01.png—the blue alien, the octopus

ALIEN_02_01.png—the red alien, the gothic cherry

ALIEN_03_01.png—the green alien, the eye

SHIP_01_01.png—the ship

7 Resize the image for the tents to 100X100 pixels square, while keeping

proportions Save it in a PNG format using the name TENT_01_01.png

8 Now, copy the newly manipulated and resized images in a

new folder (C:\Silverlight3D\Invaders\GAME_PNGS_

RESIZED), as shown in the following picture:









[ 17 ]

What just happened?

We created raster digital content for the game optimized for a 1680X1050 pixels screen We downloaded some images, and manipulated them to remove the shadows and prepare them for the game's main scene We used a naming convention for the images as we want to keep everything well organized for the game

The game will look nice using these modern raster digital art assets

Digital Content Creation tools

The Digital Content Creation tools (DCC) are very important partners for game designers and

developers They allow digital artists and graphic designers to concentrate on the creation of different kinds of digital art assets, which are then used in the applications

We can also use everything we are learning in developing the applications that have intensive graphical resources However, we will call them games in the

rest of the book

It is very easy to understand their purpose using an example If you want to show a sky with stars as an application's background, the easiest way to do it is by loading a bitmap (PNG, BMP, JPG, and so on) using the procedures or controls provided by the programming language

A digital artist will create and manipulate the sky bitmap using an image manipulation tool such as GIMP, Photoshop, or Picasa

Developing games requires the usage of a great number of resources; it is not just

programming tasks We are going to use many popular DCC tools during our journey to create Silverlight 3D games As many of these tools are very expensive, we will use some open source and free alternatives to carry out the most important tasks

A good practice before beginning 2D and 3D game development is to research the tools used to create the 2D and 3D digital content This way, we will have a better idea of how

to create the different scenes and the most common techniques Later, we will learn the programming techniques used to give life to these graphics-related operations We will be able to provide great real-time interaction to all these digital content assets, as shown in the following diagram:

Programming (loading, drawing, logic, and control)

Game

2D images 3D models Effects definitions Maps

[ 1 ]

Basic elements of a 2D and/or 3D real-time game

A modern 2D and/or 3D real-time game uses the basic elements shown in the previous diagram Let's go through them in the following list:

2D images: These can be raster bitmaps as used in our previous example, or vector graphics—also known as vector-based illustrations In some cases, they are useful as

a background made of a starry sky, or a cloudy sky In other cases, they are used as

textures to envelope different 3D objects For example, a 2D brick's image is used as

a texture to envelope a 3D object representing a wall

3D models: These contain information about the representations of primitive elements (point, lines, triangles, and polygons) to create great meshes, similar to a wire mesh that describes a 3D model Their different parts can be enveloped by textures Then everything renders in a representation in the 2D space shown by the players' screens.Effects definitions: These can be applied to 3D models to offer more realism in the production of many scenes To simplify the development process, there are many specific programming languages used to define the behavior of effects

Maps: It is easier to create real-time digital content using different kinds of maps and diverse proprietary formats Maps can specify the location of the different kinds

of houses and trees in a game that involves driving a car in a city It is possible to create many levels based on the same logic and behavior programmed for a game, but by using many different maps

Many specialized DCC tools help in creating the basic elements explained in the

aforementioned list For example, using GIMP you can see the alpha channel for the ship's PNG image, as shown in the following picture:









[ 1 ]

Programming responsibilities

We do not have to write lines of code dedicated to creating an image Instead, modern game programming focuses on the following tasks:

Loading: We must load 2D images, 3D models, textures, effects definitions, and

maps using different kinds of content loaders, parsers, import techniques, and

translators They are going to help us in transforming the original file formats to the ones supported by the programming language and the framework used to develop the game

Drawing: A game's main goal is to show real-time graphics content in a screen

One of the main problems is that 3D scenes have to be shown in a screen capable

of showing just two of these three dimensions

Logic and control: While the content is being loaded and shown, it is necessary to

apply some AI (Artificial Intelligence) to logic operations, and to provide feedback

according to the controls offered to the user for certain game actors and aspects

In order to achieve this goal, it is necessary to develop accurate time-management techniques coordinated with the information obtained from the hardware applied

to control the game—the keyboard, mouse, racing wheel, gamepad, or the Wiimote (Wii Remote), among others All of these tasks must be done while managing many heterogeneous pieces and showing a very complex audiovisual production Thus,

we must take into account everything related to the execution speed and issues

of performance

Programming games requires more knowledge about the underlying hardware on which the game will be run We must establish performance baselines and minimum requisites to achieve a desirable performance for the game Besides, we must specify the recommended

input devices to take full advantage of the game These tasks could seem pretty trivial, but

they are very important because some games are very complex and demand many difficult optimizations to be able to run on the mainstream hardware available

This is a simple summary of a game's programming responsibilities We will work through them all throughout this book

Time for action – installing tools to manipulate

scalable digital content

Your cell phone rings An old friend sees your name in the participants' list and calls you because he has some interesting information He tells you the game has to scale to huge

resolutions such as the ones found in exclusive XHD (eXtreme High Definition) displays

These displays can support resolutions as high as 2560X1600 pixels

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Scaling the raster digital assets is a big problem because pixelation becomes easily visible

If you scale the final alien for using it in a higher resolution, it will look really pixelated as shown in the following picture:

You want the game to use the entire screen space, even in the XHD displays To make this possible, you could prepare another set of raster digital assets for the game optimized for

a 2560X1600 pixels screen (4,096,000 pixels) However, the game can also be run using a 1920X1080 pixels screen (2,073,600 pixels) There is another alternative of creating a new set of scalable vector graphics (vector-based illustrations), which are ready to scale to any screen resolution without generating pixelation problems

This way, you can provide two versions of the same game—one using raster digital assets optimized for a 1680X1050 pixels screen and the other using scalable vector graphics There is no restriction in the number of games per participant Therefore, you can submit both versions

The creation of scalable vector graphics assets for a 2D game is very complex and involves professional skills We are going to simplify this process by using the existing clipart

First, we must download and install some additional tools that will help us in converting the existing scalable vector graphics to the most appropriate file formats to use in Silverlight 3:

The necessary tools will depend on the applications the digital artists use to create the scalable vector graphics However, we will be using some tools that will work fine with our examples

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1 Download the following files:

Inkscape-win32.exe

It is a very complete free, open source, vector drawing program This tool will enable us to import many vector assets in different, popular file formats and export them to a format recognized by Expression Design

2 Run the installers and follow the steps to complete the installation wizards

3 Once Inkscape's installation is finished, you will be able to load and edit many vector assets in different file formats as shown in the following picture: